Final touches are under way in front of the National Assembly in Seoul on Monday, one day ahead of the presidential inauguration ceremony there. (Yonhap)

Police launched an investigation into an online posting talking about a bomb attack at the inauguration ceremony of President Yoon Suk-yeol, officials said Tuesday.

An unidentified person wrote the posting on a popular community website, Bobaedream, Monday night, seeking an accomplice to detonate a grenade at the ceremony, the National Police Agency said.

The suspect also mentioned Yun Bong-gil, a national independence fighter who killed high-ranking Japanese officials by setting off a bomb during Japan's 1910-45 colonization of the Korean Peninsula.

The post, with more than 60 comments, has been deleted, according to the agency.

The agency said it is tracking down the identity of the writer and the case will soon be allocated to the Seocho Police Station for a formal investigation.

Yoon is set to be sworn in as South Korea's new president at the formal ceremony that is scheduled to begin at 11 a.m. at the National Assembly Plaza. (Yonhap)